/*
Copyright 2019 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package main

import (
	"context"
	"flag"
	"fmt"
	"math/rand"
	"net/http"
	_ "net/http/pprof"
	"os"
	"time"

	// +kubebuilder:scaffold:imports
	"github.com/spf13/pflag"
	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
	"k8s.io/apimachinery/pkg/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	"k8s.io/client-go/tools/leaderelection/resourcelock"
	cliflag "k8s.io/component-base/cli/flag"
	"k8s.io/component-base/logs"
	_ "k8s.io/component-base/logs/json/register"
	"k8s.io/klog/v2"
	"k8s.io/klog/v2/klogr"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller"

	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
	bootstrapv1 "sigs.k8s.io/cluster-api/bootstrap/kubeadm/api/v1beta1"
	"sigs.k8s.io/cluster-api/controllers/remote"
	controlplanev1alpha3 "sigs.k8s.io/cluster-api/controlplane/kubeadm/api/v1alpha3"
	controlplanev1alpha4 "sigs.k8s.io/cluster-api/controlplane/kubeadm/api/v1alpha4"
	controlplanev1 "sigs.k8s.io/cluster-api/controlplane/kubeadm/api/v1beta1"
	kubeadmcontrolplanecontrollers "sigs.k8s.io/cluster-api/controlplane/kubeadm/controllers"
	kcpwebhooks "sigs.k8s.io/cluster-api/controlplane/kubeadm/webhooks"
	"sigs.k8s.io/cluster-api/feature"
	"sigs.k8s.io/cluster-api/version"
)

var (
	scheme   = runtime.NewScheme()
	setupLog = ctrl.Log.WithName("setup")
)

func init() {
	klog.InitFlags(nil)

	_ = clientgoscheme.AddToScheme(scheme)
	_ = clusterv1.AddToScheme(scheme)
	_ = controlplanev1alpha3.AddToScheme(scheme)
	_ = controlplanev1alpha4.AddToScheme(scheme)
	_ = controlplanev1.AddToScheme(scheme)
	_ = bootstrapv1.AddToScheme(scheme)
	_ = apiextensionsv1.AddToScheme(scheme)
	// +kubebuilder:scaffold:scheme
}

var (
	metricsBindAddr                string
	enableLeaderElection           bool
	leaderElectionLeaseDuration    time.Duration
	leaderElectionRenewDeadline    time.Duration
	leaderElectionRetryPeriod      time.Duration
	watchFilterValue               string
	watchNamespace                 string
	profilerAddress                string
	kubeadmControlPlaneConcurrency int
	syncPeriod                     time.Duration
	webhookPort                    int
	webhookCertDir                 string
	healthAddr                     string
	etcdDialTimeout                time.Duration
	logOptions                     = logs.NewOptions()
)

// InitFlags initializes the flags.
func InitFlags(fs *pflag.FlagSet) {
	logs.AddFlags(fs, logs.SkipLoggingConfigurationFlags())
	logOptions.AddFlags(fs)

	fs.StringVar(&metricsBindAddr, "metrics-bind-addr", "localhost:8080",
		"The address the metric endpoint binds to.")

	fs.BoolVar(&enableLeaderElection, "leader-elect", false,
		"Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.")

	fs.DurationVar(&leaderElectionLeaseDuration, "leader-elect-lease-duration", 1*time.Minute,
		"Interval at which non-leader candidates will wait to force acquire leadership (duration string)")

	fs.DurationVar(&leaderElectionRenewDeadline, "leader-elect-renew-deadline", 40*time.Second,
		"Duration that the leading controller manager will retry refreshing leadership before giving up (duration string)")

	fs.DurationVar(&leaderElectionRetryPeriod, "leader-elect-retry-period", 5*time.Second,
		"Duration the LeaderElector clients should wait between tries of actions (duration string)")

	fs.StringVar(&watchNamespace, "namespace", "",
		"Namespace that the controller watches to reconcile cluster-api objects. If unspecified, the controller watches for cluster-api objects across all namespaces.")

	fs.StringVar(&profilerAddress, "profiler-address", "",
		"Bind address to expose the pprof profiler (e.g. localhost:6060)")

	fs.IntVar(&kubeadmControlPlaneConcurrency, "kubeadmcontrolplane-concurrency", 10,
		"Number of kubeadm control planes to process simultaneously")

	fs.DurationVar(&syncPeriod, "sync-period", 10*time.Minute,
		"The minimum interval at which watched resources are reconciled (e.g. 15m)")

	fs.StringVar(&watchFilterValue, "watch-filter", "",
		fmt.Sprintf("Label value that the controller watches to reconcile cluster-api objects. Label key is always %s. If unspecified, the controller watches for all cluster-api objects.", clusterv1.WatchLabel))

	fs.IntVar(&webhookPort, "webhook-port", 9443,
		"Webhook Server port")

	fs.StringVar(&webhookCertDir, "webhook-cert-dir", "/tmp/k8s-webhook-server/serving-certs/",
		"Webhook cert dir, only used when webhook-port is specified.")

	fs.StringVar(&healthAddr, "health-addr", ":9440",
		"The address the health endpoint binds to.")

	fs.DurationVar(&etcdDialTimeout, "etcd-dial-timeout-duration", 10*time.Second,
		"Duration that the etcd client waits at most to establish a connection with etcd")

	feature.MutableGates.AddFlag(fs)
}
func main() {
	rand.Seed(time.Now().UnixNano())

	InitFlags(pflag.CommandLine)
	pflag.CommandLine.SetNormalizeFunc(cliflag.WordSepNormalizeFunc)
	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
	pflag.Parse()

	if err := logOptions.ValidateAndApply(); err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	// Set the Klog format, as the Serialize format shouldn't be used anymore.
	// This makes sure that the logs are formatted correctly, i.e.:
	// * JSON logging format: msg isn't serialized twice
	// * text logging format: values are formatted with their .String() func.
	ctrl.SetLogger(klogr.NewWithOptions(klogr.WithFormat(klogr.FormatKlog)))

	if profilerAddress != "" {
		klog.Infof("Profiler listening for requests at %s", profilerAddress)
		go func() {
			klog.Info(http.ListenAndServe(profilerAddress, nil))
		}()
	}

	restConfig := ctrl.GetConfigOrDie()
	restConfig.UserAgent = remote.DefaultClusterAPIUserAgent("cluster-api-kubeadm-control-plane-manager")
	mgr, err := ctrl.NewManager(restConfig, ctrl.Options{
		Scheme:                     scheme,
		MetricsBindAddress:         metricsBindAddr,
		LeaderElection:             enableLeaderElection,
		LeaderElectionID:           "kubeadm-control-plane-manager-leader-election-capi",
		LeaseDuration:              &leaderElectionLeaseDuration,
		RenewDeadline:              &leaderElectionRenewDeadline,
		RetryPeriod:                &leaderElectionRetryPeriod,
		LeaderElectionResourceLock: resourcelock.LeasesResourceLock,
		Namespace:                  watchNamespace,
		SyncPeriod:                 &syncPeriod,
		ClientDisableCacheFor: []client.Object{
			&corev1.ConfigMap{},
			&corev1.Secret{},
		},
		Port:                   webhookPort,
		HealthProbeBindAddress: healthAddr,
		CertDir:                webhookCertDir,
	})
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	// Setup the context that's going to be used in controllers and for the manager.
	ctx := ctrl.SetupSignalHandler()

	setupChecks(mgr)
	setupReconcilers(ctx, mgr)
	setupWebhooks(mgr)

	// +kubebuilder:scaffold:builder
	setupLog.Info("starting manager", "version", version.Get().String())
	if err := mgr.Start(ctx); err != nil {
		setupLog.Error(err, "problem running manager")
		os.Exit(1)
	}
}

func setupChecks(mgr ctrl.Manager) {
	if err := mgr.AddReadyzCheck("webhook", mgr.GetWebhookServer().StartedChecker()); err != nil {
		setupLog.Error(err, "unable to create ready check")
		os.Exit(1)
	}

	if err := mgr.AddHealthzCheck("webhook", mgr.GetWebhookServer().StartedChecker()); err != nil {
		setupLog.Error(err, "unable to create health check")
		os.Exit(1)
	}
}

func setupReconcilers(ctx context.Context, mgr ctrl.Manager) {
	// Set up a ClusterCacheTracker to provide to controllers
	// requiring a connection to a remote cluster
	tracker, err := remote.NewClusterCacheTracker(mgr, remote.ClusterCacheTrackerOptions{
		Indexes: remote.DefaultIndexes,
		ClientUncachedObjects: []client.Object{
			&corev1.ConfigMap{},
			&corev1.Secret{},
			&corev1.Pod{},
			&appsv1.Deployment{},
			&appsv1.DaemonSet{},
		},
	})
	if err != nil {
		setupLog.Error(err, "unable to create cluster cache tracker")
		os.Exit(1)
	}
	if err := (&remote.ClusterCacheReconciler{
		Client:           mgr.GetClient(),
		Log:              ctrl.Log.WithName("remote").WithName("ClusterCacheReconciler"),
		Tracker:          tracker,
		WatchFilterValue: watchFilterValue,
	}).SetupWithManager(ctx, mgr, concurrency(kubeadmControlPlaneConcurrency)); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "ClusterCacheReconciler")
		os.Exit(1)
	}

	if err := (&kubeadmcontrolplanecontrollers.KubeadmControlPlaneReconciler{
		Client:           mgr.GetClient(),
		APIReader:        mgr.GetAPIReader(),
		Tracker:          tracker,
		WatchFilterValue: watchFilterValue,
		EtcdDialTimeout:  etcdDialTimeout,
	}).SetupWithManager(ctx, mgr, concurrency(kubeadmControlPlaneConcurrency)); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "KubeadmControlPlane")
		os.Exit(1)
	}
}

func setupWebhooks(mgr ctrl.Manager) {
	if err := (&controlplanev1.KubeadmControlPlane{}).SetupWebhookWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create webhook", "webhook", "KubeadmControlPlane")
		os.Exit(1)
	}

	if err := (&kcpwebhooks.ScaleValidator{
		Client: mgr.GetClient(),
	}).SetupWebhookWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create webhook", "webhook", "KubeadmControlPlane scale")
		os.Exit(1)
	}

	if err := (&controlplanev1.KubeadmControlPlaneTemplate{}).SetupWebhookWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create webhook", "webhook", "KubeadmControlPlaneTemplate")
		os.Exit(1)
	}
}

func concurrency(c int) controller.Options {
	return controller.Options{MaxConcurrentReconciles: c}
}
